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Groups > comp.lang.java.programmer > #8960
| From | Daniel Pitts <newsgroup.nospam@virtualinfinity.net> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: generics puzzle |
| References | <9g2f24Fi0vU1@mid.individual.net> <tqitm8-p04.ln1@news.simpsonst.f2s.com> <ngYmq.832$cK3.22@newsfe20.iad> <3euvm8-ee2.ln1@news.simpsonst.f2s.com> |
| Message-ID | <M%hnq.3083$Oz5.1691@newsfe16.iad> (permalink) |
| Date | 2011-10-18 09:42 -0700 |
On 10/18/11 2:45 AM, Steven Simpson wrote:
> On 17/10/11 16:58, Daniel Pitts wrote:
>> On 10/17/11 5:14 AM, Steven Simpson wrote:
>>> On 17/10/11 11:41, blmblm@myrealbox.com wrote:
>>>> One fix is to just introduce a method setFromModified() in GThing,
>>>> but that doesn't appeal to me.
>>>
>>> Instead of adding it to GThing, create a static method:
>>>
>>> private static<T> void setModified(GThing<T> t) {
>>> t.set(t.modified());
>>> }
>>
>>
>> What about the simpler solution:
>>
>> in the GThing class:
>>
>> public void setModified() {
>> set(modified());
>> }
>
> It "doesn't appeal" to the OP? Nor to me. Not sure I can put my finger
> on it, but if I were the maintainer of GThing, I'd consider its
> specification to be complete without this method. It doesn't increase
> the value of the class as an abstraction. Adding it would certainly just
> be a convenience for the caller. It solves a problem generated by the
> design of the call site, not the design of the class's contract. The
> caller can write his own routine as necessary.
>
Possibly, but if it is something that happens frequently, then it seems
more likely to belong to GThing than externally. Otherwise your
call-site is suffering from the code smell "feature envy"
One other approach is a "visitor" pattern:
public interface GThingVisitor {
<T> void visit(GThing<T> gThing);
};
public class SetModifiedGThingVisitor {
<T> void visit(GThing<T> gThing) {
gThing.set(gThing.modified());
}
}
public class GThing<T> {
public void accept(GThingVisitor visitor) {
visitor.accept(this);
}
}
public class CallSite {
public void setAllModified(Iterable<? extends GThing<?>> things) {
GThingVisitor visitor = new SetModifiedGThingVisitor();
for (GThing<?> thing: things) {
thing.accept(visitor);
}
}
}
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generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-17 10:41 +0000
Re: generics puzzle Steven Simpson <ss@domain.invalid> - 2011-10-17 13:14 +0100
Re: generics puzzle Tom Anderson <twic@urchin.earth.li> - 2011-10-17 15:14 +0100
Re: generics puzzle markspace <-@.> - 2011-10-17 07:33 -0700
Re: generics puzzle Steven Simpson <ss@domain.invalid> - 2011-10-17 16:26 +0100
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-18 14:48 +0000
Re: generics puzzle Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-10-17 15:36 +0000
Re: generics puzzle Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-10-17 08:58 -0700
Re: generics puzzle Steven Simpson <ss@domain.invalid> - 2011-10-18 10:45 +0100
Re: generics puzzle Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-10-18 09:42 -0700
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-19 13:25 +0000
Re: generics puzzle Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-10-19 10:04 -0700
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-20 14:14 +0000
Re: generics puzzle Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-10-20 11:11 -0700
Re: generics puzzle Robert Klemme <shortcutter@googlemail.com> - 2011-10-17 09:12 -0700
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-18 14:49 +0000
Re: generics puzzle Robert Klemme <shortcutter@googlemail.com> - 2011-10-18 18:27 +0200
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-18 17:45 +0000
Re: generics puzzle Robert Klemme <shortcutter@googlemail.com> - 2011-10-18 22:15 +0200
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-18 18:59 -0700
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-19 13:28 +0000
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-20 17:21 -0700
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-21 16:27 +0000
Re: generics puzzle Robert Klemme <shortcutter@googlemail.com> - 2011-10-21 20:34 +0200
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-22 18:50 +0000
Re: generics puzzle Tom Anderson <twic@urchin.earth.li> - 2011-10-22 21:02 +0100
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-25 07:04 +0000
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-25 23:25 -0700
Re: generics puzzle Tom Anderson <twic@urchin.earth.li> - 2011-10-26 21:56 +0100
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-27 08:59 +0000
eclipse shortcuts again (was Re: generics puzzle) blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-29 17:05 +0000
Re: eclipse shortcuts again (was Re: generics puzzle) Four of Seventeen <fseventeen@gmail.com> - 2011-10-29 19:49 -0700
Re: eclipse shortcuts again (was Re: generics puzzle) blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-31 11:17 +0000
Re: eclipse shortcuts again (was Re: generics puzzle) Four of Seventeen <fseventeen@gmail.com> - 2011-10-31 05:39 -0700
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-23 01:30 -0700
Re: generics puzzle Lew <lewbloch@gmail.com> - 2011-10-23 08:56 -0700
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-24 02:46 -0700
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-25 07:05 +0000
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-25 23:29 -0700
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-31 11:14 +0000
Re: generics puzzle Four of Seventeen <fseventeen@gmail.com> - 2011-10-31 05:34 -0700
Re: generics puzzle markspace <-@.> - 2011-10-18 21:21 -0700
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-19 13:29 +0000
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-20 17:22 -0700
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-21 16:28 +0000
Re: generics puzzle Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-10-21 06:22 -0300
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-21 16:29 +0000
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-23 01:20 -0700
Re: generics puzzle Martin Gregorie <martin@address-in-sig.invalid> - 2011-10-23 09:51 +0000
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-23 03:28 -0700
Re: generics puzzle Tom Anderson <twic@urchin.earth.li> - 2011-10-23 15:59 +0100
Re: generics puzzle Eight of Seventeen <eights17@gmail.com> - 2011-10-24 02:46 -0700
Re: generics puzzle Tom Anderson <twic@urchin.earth.li> - 2011-10-23 15:55 +0100
Re: generics puzzle Tom Anderson <twic@urchin.earth.li> - 2011-10-20 21:00 +0100
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-19 13:26 +0000
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-11-25 17:46 +0000
Re: generics puzzle Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-10-21 05:57 -0300
Re: generics puzzle blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2011-10-21 16:28 +0000
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